Randomised clinical trial: comparison of efficacy and adverse effects of a standard triple clarithromycin-containing regimen with high-dose amoxicillin and bismuth therapy in Helicobacter pylori eradication.

Background: The clarithromycin-based triple therapy is the most prescribed Helicobacter pylori eradication regimen in Europe; it causes adverse effects in a significant proportion of subjects, leading to discontinuation. Alternative therapies are required because of increasing clarithromycin resistance or to decrease the adverse effects.

Aims: We compared the efficacy and spectrum of adverse effects of clarithromycin-based triple therapy with the high-dose amoxicillin/bismuth regimen.

Methods: A randomised clinical trial enrolled healthy individuals aged 40-64 years. H. pylori was assessed with a 13C-urea breath test. In total 579 H. pylori-positive subjects were randomly allocated in two groups: group 1: clarithromycin 500 mg, amoxicillin 1000 mg, esomeprazole 40 mg, all twice daily; group 2: bismuth subcitrate 240 mg twice daily, amoxicillin 1000 mg three times daily, esomeprazole 40 mg twice daily. Regimens were administered for 14 days.Information on treatment completion and adverse effects were collected via a telephone interview at 21-28 days after medication delivery. The efficacy was assessed by UBT 6 months after the treatment.

Results: We analysed 483 subjects for adverse effects (248 vs. 235 respectively). Furthermore, 316 subjects were analysed for efficacy. In per-protocol analysis, a higher efficacy was seen in group 1 (88.4 vs. 77.0%; P < 0.001); no difference was observed in compliance (90.3 and 91.2%). Therapy-related adverse effects were more common in group 1 (56.9 vs. 40.0%; P < 0.01). In intention-to-treat analysis no statistical difference in efficacy was revealed.

Conclusions: Bismuth-based high-dose amoxicillin therapy showed a lower efficacy but was less frequently associated with adverse effects. Further research is required to examine the high-dose amoxicillin and bismuth-containing regimens in various populations to maximise eradication efficacy.